From the Field - Mariton Wildlife Sanctuary

Heavy Snow

Have you shoveled any of your Valentine's Day snow?  Did you think to yourself, "Boy, I must be getting old, this feels like a ton."  Well, that's what I thought with the first couple of shovels that I moved.  Then I remembered that there was several hours of sleet and freezing rain sandwiched between those layers of snow.  So, that 4" of snow had a lot more moisture in it than you would think.

When all the snow and ice in my rain gauge melted, I had 1.36" of water.  By itself, that would be a large rain event.  Under the right conditions, that could have yielded over a foot of snow.  (Of course, that would be light fluffy snow.)

Okay, I am getting old, but this makes me feel better.  That much precipitation on a 12" X 18" shovel weighs just under 11 pounds.  Scoop 100 shovels and you have moved 1/2 ton.  It makes me feel old just thinking about it.  So, don't try to shovel all the way down to the sidewalk.  Take the snow off in small slices, either horizontally or vertically.

Wind Power and Bird Fatalities

"Nocturnal Bird Migration Over an Appalachian Ridge at a Proposed Wind Power Project" is a research paper published in The Wildlife Society Bulletin October 2006.  The authors (Mabee et. al.) studied night migration along an Allegheny Frontline in West Virginia in the fall of 2003.  They used an equipment van with a roof-mounted marine radar antenna to monitor flight direction, altitude, passage rates and groundspeeds.

I was interested by several things in this paper.  For instance, I learned that resident raptors were the main fatalities at older wind powered units in the U.S.  Because of this, most modern facilities study the behavior of diurnal species when planning the layout of the windmills.  This is great.

However, there are all sorts of other birds (and bats) that use the same ridgelines at night and at different seasons of the year.  In fact, more birds migrate at night than during the day.  The authors point out that much more research needs to be done in the planning of wind powered units.  For instance, this study was conducted for 6 weeks in the fall, during peak passerine (songbird) migration, however, "most bat fatalities at wind power developments appear to occur between approximately mid-July and late September (Johnson 2004)."  I also learned that songbirds migrate at much lower altitudes than waterfowl or shorebirds.  Their research corresponded with previous research that most songbirds migrate below 600 meters (above ground level).

A few more interesting points:  Most of nocturnal use occurred from an hour after sunlight until 2:00 a.m.  They observed relatively large flights of birds on about a quarter of the nights monitored.  The mean flight altitudes were above the proposed turbine heights, however, there were 5 nights when the mean flight altitudes fell to 200-300 meters.  Birds did not seem to use the Allegheny Frontline to migrate along; rather most of their observations had birds flying across instead of parallel to the ridgeline.  The authors felt nightly variations would be explained by weather and even the species of birds migrating.  Obviously, spring migrations weren't studied in this research, but should be in the future.

I think the important point made by this research is that this equipment is capable of detecting night bird migration; and that with more baseline data humans will be able to predict where most bird strikes are likely to occur before the wind turbines are constructed.

13th Annual Migratory Census

This morning, nine birders conducted Mariton's 13th Annual Migratory Bird Census.  What a morning!  It started out cloudy and looked as if it could rain.  The clouds gradually lifted, and we ended the morning with blue skies.

We counted 58 bird species!  This is a new record for Mariton.  We also added four new species that had never been counted on this census.  They included a green heron, common merganser, bald eagle and osprey.  Granted the first three were spotted while overlooking the Delaware River.  (The osprey was actually spotted in the fields.)  The bald eagle was an immature and circled several times, so that everyone got a good look at it.  What a sighting.

We tallied 253 individuals.  This isn't a record, but is close to the average (256).  The most numerous birds were ovenbirds, at 19.  Blue jays were second with 15.  Tufted titmouses were third with 13 individuals counted.  And we got 12 scarlet tanagers.  (Not a bad day when you count a dozen tanagers.)  We counted 11 species of warblers.  While this is merely a snap shot, I think it does reflect how good Mariton's habitat is for birds.

My sincere thanks goes out to a wonderful group of birders.  Their eyes and ears were instrumental in counting this many species.  If you are interested in joining the fun, we will be doing a Nesting Bird Census on Saturday, June 3.

Fire as a Tool

A few weeks back I wrote about our Pack Test in preparation of the burn season.  During the last few weeks the Burn Crew of Natural Lands Trust has been busy using fire for ecological purposes.  When talking about fires, it is easy to confuse Wildfires with Prescribed Fires (or Controlled Burns).  The terminology is the same for both types of fire.  To add to the confusion you must get a wildfire “under control” before you put it out.  The key words are Wild and Controlled.  For Natural Lands Trust, Prescribed Fires are a tool for managing natural resources, just as a brush hog on a tractor is a tool.

Last week, I participated in burning two units at the Willisbrook Preserve on two different days.  Underneath the forest and duff at Willisbrook lies a serpentine barren in slumber.  I am no expert on Serpentine Barrens, but I know they are a unique fire-adapted habitat in Pennsylvania.  The serpentine rock that underlies this area is important to specifically adapted plant species.  When people stopped fires from naturally occurring, trees began to grow and shade out those species adapted to the Barrens.  Eventually, tree leaves and other plant materials collected and covered the rocks with duff and soil.  We use fires to remove the duff, kill the trees and hopefully one day restore those species that only occur in these serpentine barrens.

As I wrote earlier, we take these controlled burns quite seriously.  During the off-season, many days are spent preparing the units.  Things like cutting fire breaks and removing snags that could be dangerous once the fire begins.  We notify neighbors; and work with the local fire departments and the Bureau of Forestry. 

The crew assembles early on the day of the fire, and does last minute preparations.  We check our equipment.  We lay hose lines.  We fill portable tanks that are stationed in the woods, on the trucks, and on our backs.  Finally, we have a pre-burn meeting to go over weather, safety reminders, things to look for during the fire, etc.  Here is a photo of our Fire Coordinator, Darin Groff, during a pre-burn briefing.  While it may appear unorganized, each person is performing a job and listening to Darin.

Our burn units are roughly four-sided.  We have two crews that are responsible for two of the sides.  Each crew has a Crew Boss, an igniter, and people holding the fire from escaping the unit.  We use a lot of back burning (i.e. the fire works into the unit against the wind).  This makes it easier to control the fire.

Even though the Barrens may be in slumber, the fuels that we burn are very volatile.  Catbriar, or greenbriar, (Smilax rotundifolia) is very resinous and it hisses and crackles as it burns.  Being a vine, it reaches up into trees like Redcedars (Juniperous virginiana) and Virginia Pines (Pinus virginiana)that have a tendency to torch.  The grasses that grow under the trees are also very dry at this time of the year.  This isn’t a job for amateurs. We have a highly trained crew, and I feel really fortunate to be part of such a cohesive unit.  Crew members anticipate and often react before a command is given.  Getting photos during all the excitement is a little tricky, but I was able to get a few. 

After the main fire burns out, the work continues.  Armed with backpack sprayers, fire rakes, shovels and other tools, we comb the area searching for hot spots and extinguishing any lingering fires.  Late into the afternoon, when the fire is completed and the our gear is put away; we still aren’t finished.  We meet in a loose circle and have a post-fire briefing.  This is where each member offers something.  It could be something we learned from the fire.  Something we saw that we liked, or didn’t like.  Something that worked, or didn’t work.  The post fire briefing is an important part of what makes us such a dynamic and cohesive crew.

As Spring greens up the countryside, the window of opportunity for prescribed burns closes.  However, the opportunity for wildfires continues.  So be careful.

2005 Precipitation Info

During 2005, Mariton received 56.73 inches of precipitation.  The average for the last 9 years is 45.30 inches, so this is over 10 inches above average.  As unbelievable as that is, in 2003, we received 66.56 inches of precipitation. 

October was the wettest month with almost 15 inches of rainfall.  That is about double what we received in April (remember all the flooding).  We had very little flooding in October, however, because we had a very dry September.  The  October rain started when the remnants of Hurricane Tammy joined two other lows to dump over 5 inches, followed by 3+ inches the following day.

It sure seems like we have received a lot of precipitation of late.  But looking at the October 2005 records, during an 18 day period in the middle of the month, we received rain on 14 days.  Now that was a wet spell!

The driest month was September with 1.05 inches of precipitation.  May followed closely with 1.39 inches (dry for May).

February was closest to the 9 year average.  We received 3.08 inches of precipitation in February, and the average for the month is 2.98”.

Precipitation Records

It hasn’t rained at Mariton since the night of August 31.  We received over 0.80 inches of precipitation during that last week of August.  Some of this moisture was associated with Hurricane Katrina pushing gulf moisture ahead of the low.  We actually ended up with almost 4 inches for the month.

Since then it has gotten very dry.  Vegetation is beginning to wilt in Mariton’s woodland.  Fortunately, it looks as if moisture from Hurricane Ophelia will head towards the Delaware Valley later this week.  Hopefully, it will arrive as a pleasant rain and not a deluge.

Due to the nature of my job, I tend to watch the weather forecasts.  (Maureen and I also air dry all of our laundry.)  I have been keeping rainfall records since I came to Mariton.  Unfortunately, data from the early years were lost when lightning hit my computer during a thunderstorm.  But I still have complete records going back to 1997. 

At Mariton, precipitation for 2005 has been very close to average (based on data from 1997 – present).  This year, the monthly precipitation compared closely to the 8 year average for each month with two exceptions.  In April, we had about 3 inches more than average; and in May we had about 3 inches less than average.  So, those two months cancelled each other out.  At the end of August, Mariton had 1.68” surplus of precipitation for the year, compared to the 8 year average. 

Now, the precipitation here could be quite different from where you live.  My friends, Carole and Virginia, also keep rainfall records and we often compare notes.  One lives in Springtown about 4.5 miles west southwest.  The other lives in Raubsville about 2.5 miles to the north.  Mariton’s precipitation is usually within a few hundredths of an inch from one or the other.  But there are many times, especially during thunderstorm season, when all three locations differ by several tenths.  Generally, Mariton will fall in the middle, but not always. 

Tree Cookie Quiz

These tree “cookies” were taken from two trees of the same species, same forest; in fact only a few yards apart.  Can you guess which one is older?

This is a picture of Jamie Leary taken at our Nature Day Camp.  Jamie did an excellent presentation at Day Camp on our forests.  He works for the Department of Conservation and Natural Resources (DCNR) in the Bureau of Forestry.  Jamie is the Service Forester for Northampton and Monroe couties.  He wears various hats in that position, but one of his main duties is working with land owners.  If you have questions about your woodlot or forested land, your first call should be to your Service Forester.  His professional advice is free!

Jamie, like the other Service Foresters, is a wealth of knowledge.  Contact him if you are wondering  what you can do to make your forest more attractive to wildlife, or yield more firewood, or if you notice a tree disease.  Forest owners are often approached by loggers, and amazed at how much the timber is worth.  But before you sign any contracts, contact your Service Forester.  Remember his experience is free.  Your Service Forester can walk you through the contract and help you make sure that the forest cutting is managed to your goals, and not the logger’s.  Even if you never plan to harvest your timber, you should make an appointment to walk your woods with your Service Forester.  They see interesting things that are important to your forest’s health.  Besides, it is a lot of fun to walk through the woods with them, to see the forest through their eyes.

Back to the tree cookies.  The smaller one is older.  It was 29 years old; the bigger tree was 26 years old. 

You will often hear people say that you need to cut out the big trees to let light in, so the younger trees can start growing.  Not necessarily so.  These two trees were about the same age, and one was much better at utilizing resources than the other one.  Before you knew their ages, you might have cut the bigger tree to allow space for the smaller one to grow.  But the smaller (older) tree will probably never reach its potential.  If you leave the bigger one, it can drop acorns and pass its genes onto the next generation of forest.  And I learned that from my Service Forester.

My thanks to Carole Mebus, who took these photos, and many more, to document our Nature Day Camps.

Counting Butterflies

It was a great day to count butterflies.  We had a good group of counters, with a couple seasoned veterans.  Then, we had a couple folks like me, who know a handful of species, but struggle with the different skippers (they look too similar and fly too quickly).  I was really pleased to identify a southern cloudy wing correctly.  That means that there is hope for everyone! 

We tallied 21 different butterfly species, and counted 172 individual butterflies.  We had several that got away before we were able to identify them.  We don't use nets, but rather binoculars that can focus to a few feet.  We have counted 22 species on three previous counts, so 21 is a good count. 

Great spangled fritillaries were the high species with 55 butterflies.  It is a long name, but they are beautifly butterflies that are abundant at Mariton.  When their wings are closed, you can see the silver spots (or spangles).  When open or flying, you see orange.  We only counted 45 cabbage whites.  Silver- spotted skippers came in at 14.

Like bird censuses, a butterfly census is only a snapshot in time.  If we counted in the afternoon, we might pick up some different species and loose some species from the morning count.  In a year with lots of milkweed blooming, we would get different numbers, than a year with very few blooms, etc.  But over years it does give us an idea of what butterfly species one should be able to find in late June.  So, it provides important baseline data.  This can be interesting when looking at trends, more than comparing one year against another. 

Here is a photo of a hackberry emperor.  These are “friendly” butterflies, readily landing on people and light colored clothing. 

Migratory Bird Census

This morning, we conducted Mariton’s 13^th Annual Migratory Count.  We tallied 53 species and 229 individuals.  Fifty-three species is the fourth highest count (the average is 49 species).  The average number of individual birds for the 13 counts is 256 individuals. 

Mid-May is near the peak of migration, when one can see the most species.  Most birders are saying that the warbler migration has been slow this spring, and I would agree.  We counted 14 warbler species in 1999 (the year with the highest species count); this year we counted 10 warbler species. What is really noticeable is that the number of birds seems down, at least for some species.  On the bright side, we may be in for a stretched-out warbler migration.

I would like to thank Bill Wallace, Virginia Derbyshire, Carole Mebus and Anne Hogenboom for volunteering their eyes, ears, and knowledge.  The census would not be as thorough without dedicated volunteers.  Plus, I really enjoy their company.

Here is a sampling of the some of the birds that we counted this morning (the complete count is posted in the Nature Center):  black-billed cuckoo, 6 black-throated blue warblers (that is a lot), Blackburnian warbler, chestnut-sided warbler, 16 ovenbirds, and 9 rose - breasted grosbeaks.  We spotted a great blue heron flying overhead, and yes we counted it.

We will be doing a Nesting Bird Census on June 4.  There probably won’t be as many species (although this year may be different), but it will certainly be interesting.  Bring your binoculars and help us count the birds! 

After the Flood

On April 4 (see April Flooding), I posted 3 pictures taken from the  River Lookout trail, and at the base of the cliffs.  Shown  here are photographs taken from approximately the same locations, after the river returned to its banks.  The river is still high, but you can imagine the impact of the flood by comparing the photos.

 

Finally, here is a picture of Tom Kershner (on the right) and Rebecca Shields Moose standing on Route 611, beside a section of the wall.  We took advantage of the road closure to cut some trees that I felt could compromise the integrity of the stone wall.  The flood waters actually topped this section of wall, which is 7 feet above the road surface.  Tom is the Preseve Manager at Gwynedd Wildlife Preserve, and is also Natural Lands Trust's arborist.  Rebecca is one of four Stewardship Assistants.  These folks visit the different preserves and help Preserve Managers "get the job done".